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Abstract. In this paper, an extensive review has been carried out on the trends of existing as well as proposed potential enabling technologies that are expected to shape the fifth generation (5G) mobile wireless networks. Based on the classification of the trends, we develop a 5G network architectural evolution framework that comprises three evolutionary directions, namely, (1) radio access network node and performance enabler, (2) network control programming platform, and (3) backhaul network platform and synchronization. In (1), we discuss node classification including low power nodes in emerging machine-type communications, and network capacity enablers, e.g., millimeter wave communications and massive multiple-input multiple-output. In (2), both logically distributed cell/device-centric platforms, and logically centralized conventional/wireless software defined networking control programming approaches are discussed. In (3), backhaul networks and network synchronization are discussed. A comparative analysis for each direction as well as future evolutionary directions and challenges toward 5G networks are discussed. This survey will be helpful for further research exploitations and network operators for a smooth evolution of their existing networks toward 5G networks.

We develop on-line routing and wavelength assignment (RWA) algorithms for WDM bidirectional ring and torus networks with N nodes. The algorithms dynamically support all k-allowable traffic matrices, where k denotes an arbitrary integer vector [k1, k2, ..., kN ], and node i, 1 ≤ i ≤ N , can transmit at most ki wavelengths and receive at most ki wavelengths. Both algorithms support the changing traffic in a rearrangeably nonblocking fashion. Our first algorithm, for a bidirectional ring, uses (N i=1 ki)/3 wavelengths in each ring direction and requires at most three lightpath rearrangements per new session request regardless of the number of nodes N and the amount of traffic k. When all the ki's are equal to k, the algorithm uses kN/3 wavelengths, which is known to be the minimum for any off-line rearrangeably nonblocking algorithm. Our second algorithm, for a torus topology, is designed for the special case with all the ki's equal to k. For a square torus network with N nodes, the algorithm uses k √ N/2 wavelengths in each fiber, which is shown to be at most two times a lower bound obtained by assuming full wavelength conversion at all nodes. In addition, the algorithm requires at most √ N −1 lightpath rearrangements per new session request regardless of the amount of traffic k.

The vast acceptance of OFDM technology is not limited to the radio domain, but is also among researchers for wireline and wireless optical communications. For indoor wireless optical communications, the use of OFDM faces a major challenge in reducing the average transmit optical power to cope with the eye safety problem. We propose the use of the selected mapping (SLM) technique to reduce the average transmit optical power in indoor WOC systems. In particular, SLM is investigated by employing five different families of phase sequences, namely chaotic, Shapiro-Rudin, pseudo-random interferometry code (PRIC), Walsh-Hadamard, and random sequences. Simulation results indicate the attractiveness of chaotic and Shapiro-Rudin sequences in terms of the reduction in the average transmit power with the computational complexity that grows linearly with the number of OFDM subcarriers.

Radio Access Network (RAN) costs savings are expected in future Cloud RAN (C-RAN). Differently from traditional distributed RAN architecture, in C-RAN Remote Radio Heads (RRH) from different sites can share baseband processing resources from virtualized Base Band Unit (BBU) pools placed in few central locations (CO). Due to the\ud stringent requirements of the several interfaces needed in C-RAN, optical networks have been proposed to support it. In this paper, we present the C-RAN Capital Expenditures (CAPEX) minimization problem to decide which COs should be equipped and the equipment to be installed. Several problem instances considering different Long Term\ud Evolution-Advanced (LTE-A) configurations are solved to study the impact of the centralization level C-RAN in terms of both, CAPEX and Operational Expenditures (OPEX). Compared to the maximum centralization level, results showed remarkable costs savings when a lower level of centralization is considered.Peer ReviewedPostprint (published version

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